Pressurized, integrated electrochemical converter energy system

ABSTRACT

An electrochemical converter is disposed within a pressure vessel that collects hot exhaust gases generated by the converter for delivery to a cogeneration bottoming device, such as a gas turbine. The bottoming device extracts energy from the waste heat generated by the converter, such as a fuel cell for the generation of electricity, yielding an improved efficiency energy system. Bottoming devices can include, for example, a gas turbine system or an heating, ventilation or cooling (HVAC) system. The pressure vessel can include a heat exchanger, such as a cooling jacket, for cooling the pressure vessel and/or preheating an input reactant to the electrochemical converter prior to introduction of the reactant to the converter. In one embodiment, a compressor of a gas turbine system assembly draws an input reactant through the pressure vessel heat exchanger and delivers the reactant under pressure to a fuel cell enclosed therein. Pressurized and heated fuel cell exhaust gases are collected by the pressure vessel and delivered to the turbine system expander. The fuel cell and the pressure vessel function as the combustor of the gas turbine assembly. The expander can perform mechanical work, or can be coupled to a generator to provide electrical energy in addition to that provided by the fuel cell. Also disclosed is a feedthrough for transferring a fluid, such as exhaust gases or an input reactant, from outside the pressure vessel to within the pressure vessel.

REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 U.S.C. 119(e) to co-pendingU.S. Provisional Application No. 60/034,836, entitled "Pressurized,Integrated Electrochemical Converter System", filed Dec. 31, 1996, thecontents of which are hereby incorporated by reference; and is acontinuation-in-part application of U.S. application Ser. No.08/325,486, now U.S. Pat. No. 5,693,201, entitled "Ultra High EfficiencyTurbine And Fuel Cell Combination," filed Oct. 19, 1994, the contents ofwhich are also incorporated by reference. U.S. application Ser. No.08/325,486 is a continuation-in-part of U.S. patent application Ser. No.08/287,093, entitled "Electrochemical Converter Having Internal ThermalIntegration", filed Aug. 8, 1994, and issued as U.S. Pat. No. 5,501,781on Mar. 26, 1996, and which is also incorporated by reference.

BACKGROUND

This invention relates to high temperature electrochemical converters,such as fuel cells, and more specifically to high performance energy, orpower, systems that employ electrochemical converters.

Electrochemical converters, such as fuel cells, convert chemical energyderived from fuel stocks directly into electrical energy. One type offuel cell includes a series of electrolyte units, onto which fuel andoxidizer electrodes are attached, and a similar series ofinterconnectors disposed between the electrolyte units to provideelectrical connections. Electricity is generated through electrodes andthe electrolyte by an electrochemical reaction that is triggered when afuel, e.g., hydrogen, is introduced over the fuel electrode and anoxidant, e.g., air, is introduced over the oxidizer electrode.Alternatively, the electrochemical converter can be operated in anelectrolyzer mode, in which the electrochemical converter consumeselectricity and input reactants and produces fuel.

When an electrochemical converter, such as a fuel cell, performsfuel-to-electricity conversion in a fuel cell mode, waste energy isgenerated and should be properly processed to maintain the properoperating temperature of the electrochemical converter and to boost theoverall efficiency of the power system. Conversely, when the converterperforms electricity-to fuel conversion in the electrolyzer mode, theelectrolyte must be provided with heat to maintain its reaction.Furthermore, the fuel reformation process, often used with fuel cells,can require the introduction of thermal energy. Thus thermal managementof the electrochemical converter system for proper operation andefficiency is important.

Thermal management techniques can include the combination of anelectrochemical converter with other energy devices in an effort toextract energy from the waste heat of the converter exhaust. Forexample, U.S. Pat. No. 5,462,817, issued to Hsu describes certaincombinations of electrochemical converters and bottoming devices thatextract energy from the converter for use by the bottoming device.

Environmental and political concerns associated with traditionalcombustion-based energy systems, such as coal or oil fired electricalgeneration plants, are boosting interest in alternative energy systems,such as energy systems employing electrochemical converters.Nevertheless electrochemical converters have not found widespread use,despite significant advantages over conventional energy systems. Forexample, compared to traditional energy systems, electrochemicalconverters such as fuel cells, are relatively efficient and do notproduce pollutants. The large capital investment in conventional energysystems necessitates that all advantages of competing energy systems berealized for such systems to find increased use. Accordingly,electrochemical converter energy systems can benefit from additionaldevelopment to maximize their advantages over traditional energy systemsand increase the likelihood of their widespread use.

Accordingly, it is an object of the present invention to increase theefficiency of an energy system that employs an electrochemicalconverter.

It is yet another object of the invention to simplify energy systemsthat employ electrochemical converters.

It is yet a further object of the invention to provide a simplified andimproved electrochemical converter energy system that extracts energyfrom waste heat generated by the electrochemical converter.

Although electrochemical converters have significant advantages overconventional energy systems, for example, they are relatively efficientand do not produce pollutants that have not yet found widespread use.

SUMMARY OF THE INVENTION

The present invention attains the foregoing and other objects byproviding methods and apparatus for more efficiently operating an energysystem that employs an electrochemical converter. According to theinvention, an electrochemical converter, such as a fuel cell, iscombined with a cogeneration or bottoming device that extracts energyfrom the waste heat produced by the fuel cell. The electrochemicalconverter and the bottoming device form an improved energy system forconverting fuel into useful forms of electrical, mechanical, or thermalenergy. Devices that may be combined with a fuel cell include gasturbines, steam turbines, thermal fluid boilers, and heat-actuatedchillers. The latter two devices are often incorporated in a HeatingVentilation and Cooling (HVAC) system.

According to one aspect of the invention, an electrochemical converteris disposed within a positive pressure vessel that is adapted forcollecting heated exhaust gases produced by the electrochemicalconverter. At least a portion of the exhaust gases generated by theelectrochemical converter are exhausted into the interior of thepressure vessel for collection by the vessel, and the pressure vesselincludes an exhaust element for routing the collected gases to abottoming device. The positive pressure vessel allows the exhaust gasesgenerated by the electrochemical converter to be collected attemperatures and pressures suited for the extraction of energy bybottoming devices. Such devices include, but are not limited to, a gasturbine, a thermal fluid boiler, a steam boiler, and a heat-actuatedchiller. Thus the invention facilitates the integration of aelectrochemical converter, such as a fuel cell array, with bottomingdevices.

The term "positive pressure vessel" is intended to include a vesseldesigned to operate at pressures such as 1 or 2 atmospheres, or a vesseldesigned to tolerate much higher pressures, up to 1000 psi. A lowerpressure vessel is useful when the bottoming device used in conjunctionwith the electrochemical converter is, for example, an HVAC system thatincorporates a heat-actuated chiller or a boiler. A higher pressurevessel is useful, for example, with a gas turbine.

According to another aspect of the invention, a pump mechanism pumps atleast one of the input reactants into the electrochemical converter suchthat pressurized exhaust exits the converter and pressurizes theinterior of the pressure vessel. In one aspect of the invention, thepump can be the compressor of a gas turbine, and the pressure vessel andelectrochemical converter enclosed therein function as a combustor forthe turbine. The exhaust gases collected by the pressure vessel aredelivered to, and drive, the turbine. The turbine may be coupled to anelectric generator to produce electric energy in addition to thatproduced directly by the electrochemical converter.

Alternatively, in a different aspect of the invention, theabove-mentioned pump can be a blower that pressurizes the interior ofthe pressure vessel for optimum delivery of the exhaust gases to theheating element, such as a thermal fluid or steam boiler, or the coolingelement, such as a heat-actuated chiller, of an HVAC system.

In yet a further aspect of the invention, the energy system of theinvention includes a regenerative heat exchanging element, such as acooling jacket, in thermal communication with a pressure vessel, formaintaining the exterior of the vessel at a selected temperature. A heatexchanging fluid is circulated through the cooling jacket, typically bya pump. According to this feature of the invention, the regenerativeheat exchanger cools the exterior of the pressure vessel.

According to another feature of the invention, reactants, such as thosesupplied to the fuel cell array or reactant processors, are passedthrough the cooling jacket of the pressure vessel prior to theirintroduction to the electrochemical converter. These reactants arepreheated by the heat exchanger prior to introduction to a fuel cell orreactant processor.

In yet another aspect, the reactants are drawn through the heatexchanging element by a drawing pump, and the outlet of the pumpsupplies the reactant to a fuel cell or reactant processor.Significantly, the drawing pump can be the compressor of a gas turbinethat also extracts energy from the waste heat from the converter. Theinlet of the compressor is in fluid communication with the heatexchanging element to draw a reactant, such as air, through the heatexchanging elements. The outlet of the compressor is in fluidcommunication with the fuel cell array, or with a reactant processor,for supplying the heated reactant thereto. The pressurized exhaust gasesare collected by the pressure vessel and supplied to the gas turbine.

In another aspect of the invention, the input reactant is blown, or inan alternative embodiment drawn, through the heat exchanging element bya blower. The blower provides a slight pressurization of vessel tofacilitate collection and delivery of the electrochemical converterexhaust gases to a bottoming device, such as a HVAC system, that caninclude a heat actuated chiller and/or a boiler.

Both the compressor, which is typically used with a turbine, and theblower, pressurize the vessel by forcing input reactant into, and henceexhaust products out of, the electrochemical converter, which exhauststo the interior of the vessel. Because the blower does not significantlyheat the reactants, it can be arranged to blow, rather than draw, a heatexchanging fluid comprising an input reactant or reactants through theheat exchanging element for cooling the vessel.

The invention provides a simplified electrochemical converter powersystem with enhanced efficiency by providing a pressure vessel for thecollection of exhaust gases and by minimizing the need for anindependent cooling system for cooling the exterior of the pressurevessel. Such an independent system would typically include a pump,cooling fluid, and a radiator dedicated solely to removing heat from thepressure vessel heat exchanger. The invention employs an input reactantas the cooling fluid, eliminating the need for dedicated cooling fluid.In addition, waste heat is introduced to the input reactant stream,eliminating the need for a separate heat exchanger and re-introducingwaste heat to the converter assembly, thus boosting efficiency. Theinput reactant can be drawn through the pressure vessel heat exchangingelement by the compressor, or blown through by an air blower, thuseliminating the need for a separate pump to circulate the heatexchanging fluid.

In yet another aspect of the invention, the heat exchanger of thepresent invention is a tubular coil, in thermal communication with thepressure vessel, and having an interior lumen. The heat exchanging fluidflows through the inner lumen of the tubular coil. In another variationof the present invention, the heat exchanger includes a porousstructure, and the pressure vessel transpirationally exchanges heat asthe heat exchanging fluid flows through the pores of the wall. One ofordinary skill in the art, based on the disclosures herein, can envisionother heat exchangers useful for exchanging heat with the pressurevessel. See for example, Internal Thermal Integration (ITI), describedin U.S. Pat. No. 5,501,781, herein incorporated by reference, andRadiant Thermal Integration, (RTI) described in U.S. Pat. No. 5,462,817,herein incorporated by reference. Additional thermal control systemsemploying isothermal heat exchangers are disclosed in U.S. Pat. No.5,338,622, also herein incorporated by reference. Modification of suchtechniques for the exchange of heat with the pressure vessel, inaccordance with the disclosure herein is considered within the scope ofthe invention.

In yet another aspect of the invention, feedthroughs are provided forducting reactants from the outside of the pressure vessel to theelectrochemical fuel cell array disposed within the pressure vessel andvice versa. Similarly, feedthroughs are provided for making electricalconnections to the electrochemical converter array, and for exhaustingexhaust products generated by the electrochemical converter array. Thefeedthroughs for handling the reactants are adapted to provide atransition from a high pressure, high temperature environment within thepressure vessel to an environment exterior to the pressure vessel.

The foregoing and other objects, features and advantages of theinvention will be apparent from the following description and apparentfrom the accompanying drawings, in which like reference characters referto the same parts throughout the different views. The drawingsillustrate principles of the invention and, although not to scale, showrelative dimensions.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic block diagram of one embodiment of an energysystem employing an electrochemical converter and a gas turbineaccording to the present invention;

FIG. 2 is a schematic block diagram of another embodiment of an energysystem employing an electrochemical converter, such as a fuel cell,thermally coupled with a heating or cooling component of an HVAC system;

FIG. 3 is a perspective view of a basic cell unit of an electrochemicalconverter useful with the present invention;

FIG. 4 is a perspective view of an alternate embodiment of the basiccell unit of the electrochemical converter of the present invention;

FIG. 5 is a cross-sectional view of the cell unit of FIG. 3;

FIG. 6 is a plan view, partially cut-away, of a pressure vesselenclosing a series of electrochemical converters of the presentinvention;

FIG. 7 is a cross section of a feedthrough for use with the pressurevessel of FIG. 6; and

FIG. 8 is a schematic illustration of an energy system incorporating anelectrochemical converter disposed within a pressure vessel, a pressurevessel heat exchanger, and a gas turbine system for extracting energyfrom exhaust gases generated by the converter.

DESCRIPTION OF ILLUSTRATED EMBODIMENTS

FIG. 1 shows an energy system incorporating an electrochemical converterand a gas turbine according to the present invention. The illustratedenergy system 70 includes an electrochemical converter 72 and a gasturbine assembly 71.

The gas turbine assembly 71 includes a compressor 76, a turbine expander80, and a generator 84. Air from air source 73 is introduced to thecompressor 76, by way of any suitable conduit, where it is compressed,heated in the air preheater 69 and discharged and introduced to theelectrochemical converter 72. The fuel 74 is introduced to a reformer 68where it is reformed, as is known in the art, and is then directed tothe electrochemical converter 72. The heated air and fuel function asinput reactants and power the electrochemical converter 72.

The converter 72 receives the compressed air introduced by thecompressor 76, and the fuel 74, thermally disassociating it in thereformer 68 into constituent non-complex reaction species, typically H₂and CO, before using the fuel and air to produce electrical power and ahigh temperature exhaust. The exhaust is introduced to the interior of apressure vessel 77, which collects and routes the exhaust 79 to the gasturbine expander 80, which converts this thermal energy into rotaryenergy, for subsequent transfer to an electric generator 84. Thegenerator 84 produces electricity that can be used for both industrialand residential purposes. The converter 72 functions as an additionalelectric generator, and the illustrated electrical connections 88A and88B show that electricity can be extracted from both the generator 84and the converter 72. The gas turbine assembly 71 components and thegenerator 84 are known and commercially available. Those of ordinaryskill will readily understand the integration of the electrochemicalconverter 72 and the gas turbine assembly 71, in light of the presentdescription and illustrations.

FIG. 2 shows a total energy system 90 incorporating an electrochemicalconverter and an Heating, Ventilation, and Cooling (HVAC) system. Thetotal energy system 90, in addition to producing electricity,conditions, e.g., heats or cools, a selected fluid. The illustratedtotal energy system 90 includes an electrochemical converter 72 that isthermally coupled to an HVAC system 92. The electrochemical converter72, in addition to generating electricity, produces waste heat which istransferred, either radiatively, convectively, or conductively, to theHVAC system 92. The electrochemical converter 72 shown in FIG. 2 isconvectively coupled to the HVAC system 92.

HVAC systems, such as the illustrated HVAC system 92, commonly utilize aclosed loop system for transferring a heat transfer fluid throughout abuilding or an industrial facility. In such a closed loop system, aheating component, such as a steam boiler or a thermal fluid boiler, ora cooling component, such as a heat actuated chiller or other airconditioning component, conditions the heat transfer fluid, which istypically conveyed throughout the facility via fluid conduits. HVACsystems are commonly used for controlling the ambient environmentalconditions, such as temperature or humidity, in one or a plurality ofstructurally enclosed facilities. According to one common practice, aplurality of HVAC systems can be installed within a single facility andare connected in a suitable network which is serviced by a commonthermal source, which may include either a heating component or acooling component, or both. The heating and cooling components providethe thermal energy required to heat or cool the facility.

The illustrated electrochemical converter 72, e.g., a fuel cell, has afuel reactant input 74 and an air reactant input 73. The fuel andoxidizer reactants are introduced to the illustrated electrochemicalconverter 72 by way of appropriate manifolding. The electrochemicalconverter processes the fuel and oxidizer reactants. 74 and 73,respectively, and generates, in one mode of operation, electricity andwaste heat.

As shown, the illustrated electrochemical converter 72 produces exhaust99 containing waste heat, which is delivered from the electrochemicalconverter 72 to the interior of a pressure vessel 95 disposed about theelectrochemical converter 72. The pressure vessel 95 collects theexhaust 99 and delivers it to the thermal process element 96 for usewith the heating or cooling component 94 of the HVAC system 92,convectively integrating the converter 72 with the HVAC system 92. Thethermal process element 96 can include, for example, a convective heatexchanger that is geometrically matched to a vapor generator (not shown)of a heat-actuated chiller, such that the convective heat exchangerabsorbs heat from the exhaust 99 and transfers the heat to the vaporgenerator. The vapor generator can be in the shape of an annulus, andthe convective heat exchanger can be positioned in the center of theannulus. After exiting the thermal process element 96, the exhaust isthen ducted away from the system.

A blower 98 can be employed to pump an input reactant, such as the airinput reactant 73, into the electrochemical converter 72 and to producea higher pressure flow of exhaust 99 within the pressure vessel 95 andhence delivered to the HVAC system 92. Alternatively, a drawing pump 100can draw exhaust gases 99 from the electrochemical converter 72 andpressure vessel 95 for supply to the HVAC system 92. The pressure vessel95 used with energy system illustrated in FIG. 2 is typically designedto operate at lower pressure than the pressure vessel 77 illustrated inFIG. 1.

Energy systems, such as those illustrated in FIGS. 1 and 2, can achievehigh efficiency by the direct integration of a compact electrochemicalconverter with bottoming plant components. For example, the integrationof the electrochemical converter with a gas turbine in the mannerillustrated in FIG. 1 produces a hybrid power system that has an overallpower efficiency of nearly about 70%. This system efficiency representsa significant increase over the efficiencies achieved by conventionalgas turbine systems and prior art electrochemical systems. Theelectrochemical converter 72 also operates as a low NOx thermal source,thereby improvings environmental performance relative to a conventionalgas turbine generating system.

The electrochemical converter of the present invention is preferably afuel cell, such as a solid oxide fuel cell, a molten carbonate fuelcell, a phosphoric acid fuel cell an alkaline fuel cell or a protonexchange membrane fuel cell. Electrochemical converters, such as fuelcells, are known in the art, and are shown and described in U.S. Pat.No. 5,462,817 of Hsu, U.S. Pat. No. 5,501,781 of Hsu, and U.S. Pat. No.4,853,100 of Hsu, all of which are hereby incorporated by reference.

The above discussion is illustrative of energy systems that employelectrochemical converters disposed within a pressure vessel forcollection of exhaust gases that are then delivered to bottoming devicesto realize a higher efficiency energy system. The above illustration ofFIGS. 1 and 2 are not intended to be limiting; additional energy systemscan be used in accord with the teachings of the present invention. Forexample, U.S. Pat. No. 5,501,781 of Hsu et. al. and U.S. Pat. No.6,462,817 of Hsu disclose energy systems employing an electrochemicalconverter and a steam generator, amongst other energy systems.

As noted above, the electrochemical converters useful with the presentinvention include fuel cells. Fuel cells typically utilize the chemicalpotential of selected fuel species, such as hydrogen or carbon monoxidemolecules, to produce oxidized molecules in addition to electricalpower. Because the cost of supplying molecular hydrogen or carbonmonoxide is relatively higher than providing traditional fossil fuels, afuel processing or reforming step can be utilized to convert the fossilfuels, such as coal and natural gas, to a reactant gas mixture high inhydrogen and carbon monoxide. Consequently, a fuel processor, eitherdedicated or disposed internally within the fuel cell, is employed toreform, by the use of steam, oxygen, or carbon dioxide (in anendothermic reaction), the fossil fuels into non-complex reactant gases.

FIGS. 3-5 illustrate, as an example, the basic cell unit 110 of theelectrochemical converter 72, which is particularly suitable forintegration with conventional gas turbines. The cell unit 110 includesan electrolyte plate 120 and an interconnector plate 130. Theelectrolyte plate 120 can be made of a ceramic, such as a stabilizedzirconia material ZrO₂ (Y₂ O₃), on which a porous oxidizer electrodematerial 120A and a porous fuel electrode material 120B are disposedthereon. Exemplary materials for the oxidizer electrode material areperovskite materials, such as LaMnO₃ (Sr). Exemplary materials for thefuel electrode material are cermets such as ZrO₂ /Ni and ZrO₂ /NiO.

The interconnector plate 130 preferably is made of an electrically andthermally conductive interconnect material. Examples of such materialinclude nickel alloys, platinum alloys, non-metal conductors such assilicon carbide, La(Mn)CrO₃, and preferably commercially availableInconel, manufactured by Inco., U.S.A. The interconnector plate 130serves as the electric connector between adjacent electrolyte plates andas a partition between the fuel and oxidizer reactants. As best shown inFIG. 4, the interconnector plate 130 has a central aperture 132 and aset of intermediate, concentric radially outwardly spaced apertures 134.A third outer set of apertures 136 are disposed along the outercylindrical portion or periphery of the plate 130.

The interconnector plate 130 has a textured surface 138. The texturedsurface preferably has formed thereon a series of dimples 140, as shownin FIG. 4, which form a series of connecting reactant-flow passageways.Preferably, both sides of the interconnector plate 130 have the dimpledsurface formed thereon. Although the intermediate and outer set ofapertures 134 and 136, respectively, are shown with a selected number ofapertures, those of ordinary skill will recognize that any number ofapertures or distribution patterns can be employed, depending upon thesystem and reactant-flow requirements.

Likewise, the electrolyte plate 120 has a central aperture 122, and aset of intermediate and outer apertures 124 and 126 that are formed atlocations complementary to the apertures 132, 134 and 136, respectively,of the interconnector plate 130.

Referring to FIG. 4, a spacer plate 150 can be interposed between theelectrolyte plate 120 and the interconnector plate 130. The spacer plate150 preferably has a corrugated surface 152 that forms a series ofconnecting reactant-flow passageways, similar to the interconnectingplate 130. The spacer plate 150 also has a number of concentricapertures 154, 156, and 158 that are at locations complementary to theapertures of the interconnect and electrolyte plates, as shown. Further,in this arrangement, the interconnector plate 130 is devoid ofreactant-flow passageways. The spacer plate 150 is preferably made of anelectrically conductive material, such as nickel.

The illustrated electrolyte plates 120, interconnector plates 130, andspacer plates 150 can have any desirable geometric configuration.Furthermore, the plates having the illustrated manifolds can extendoutwardly in repetitive or non-repetitive patterns, and thus are shownin dashed lines.

Referring to FIG. 5, when the electrolyte plates 120 and theinterconnector plates 130 are alternately stacked and aligned alongtheir respective apertures, the apertures form axial (with respect tothe stack) manifolds that feed the cell unit with the input reactantsand that exhaust spent fuel. In particular, the aligned centralapertures 122, 132, 122 of FIGS. 3 and 4 form input oxidizer manifold117, the aligned concentric apertures 124, 134, 124 of FIGS. 3 and 4form input fuel manifold 118, and the aligned outer apertures 126, 136,126 of FIGS. 3 and 4 form spent fuel manifold 119.

The dimpled surface 138 of the interconnector plate 130 has, in thecross-sectional view of FIG. 5, a substantially corrugated patternformed on both sides. This corrugated pattern forms the reactant-flowpassageways that channel the input reactants towards the periphery ofthe interconnector plates. The interconnector plate also has an extendedheating surface or lip structure that extends within each axial manifoldand about the periphery of the interconnector plate. Specifically, theinterconnector plate 130 has a flat annular extended surface 131A formedalong its outer peripheral edge. In a preferred embodiment, theillustrated heating surface 131A extends beyond the outer peripheraledge of the electrolyte plate 120. The interconnector plate further hasan extended heating surface that extends within the axial manifolds, forexample, edge 131B extends into and is housed within the axial manifold119; edge 131C extends into and is housed within the axial manifold 118;and edge 131D extends into and is housed within the axial manifold 117.The extended heating surfaces can be integrally formed with theinterconnector plate or can be coupled or attached thereto. The heatingsurface need not be made of the same material as the interconnectorplate, but can comprise any suitable thermally conductive material thatis capable of withstanding the operating temperature of theelectrochemical converter. In an alternate embodiment, the extendedheating surface can be integrally formed with or coupled to the spacerplate.

The absence of a ridge or other raised structure at the interconnectorplate periphery provides for exhaust ports that communicate with theexternal environment. The reactant-flow passageways connect, fluidwise,the input reactant manifolds with the outer periphery, thus allowing thereactants to be exhausted to the external environment, or to a thermalcontainer or pressure vessel disposed about the electrochemicalconverter, as discussed below.

Referring again to FIG. 5, the illustrated sealer material 160 can beapplied to portions of the interconnector plate 130 at the manifoldjunctions, thus allowing selectively a particular input reactant to flowacross the interconnector surface and across the mating surface of theelectrolyte plate 120. The interconnector plate bottom 130B contacts thefuel electrode coating 120B of the electrolyte plate 120. In thisarrangement, it is desirable that the sealer material only allow fuelreactant to enter the reactant-flow passageway, and thus contact thefuel electrode.

As illustrated, the sealer material 160A is disposed about the inputoxidizer manifold 117, forming an effective reactant flow barrier aboutthe oxidizer manifold 117. The sealer material helps maintain theintegrity of the fuel reactant contacting the fuel electrode side 120Bof the electrolyte plate 120, as well as maintain the integrity of thespent fuel exhausted through the spent fuel manifold 119.

The top 130A of the interconnector plate 130 has the sealer material160B disposed about the fuel input manifolds 118 and the spent fuelmanifold 119. The top of the interconnector plate 130A contacts theoxidizer coating 120B' of an opposing electrolyte plate 120'.Consequently, the junction at the input oxidizer manifold 117 is devoidof sealer material, thereby allowing the oxidizer reactant to enter thereactant-flow passageways. The sealer material 160B that completelysurrounds the fuel manifolds 118 inhibits the excessive leakage of thefuel reactant into the reactant-flow passageways, thus inhibiting themixture of the fuel and oxidizer reactants. Similarly, the sealermaterial 160C that completely surrounds the spent fuel manifold 119inhibits the flow of spent oxidizer reactant into the spent fuelmanifold 119. Hence, the purity of the spent fuel that is pumped throughthe manifold 119 is maintained.

Referring again to FIG. 5, the oxidizer reactant can be introduced tothe electrochemical converter through axial manifold 117 that is formedby the apertures 122, 132, and 122' of the electrolyte andinterconnector plates, respectively. The oxidizer is distributed overthe top of the interconnector plate 130A, and over the oxidizerelectrode surface 120A' by the reactant-flow passageways. The spentoxidizer then flows radially outward toward the peripheral edge 131A,and is finally discharged along the converter element periphery. Thesealer material 160C inhibits the flow of oxidizer into the spent fuelmanifold 119. The flow path of the oxidizer through the axial manifoldsis depicted by solid black arrows 126A, and through the oxidizer cellunit by the solid black arrows 126B.

The fuel reactant is introduced to the electrochemical converter 110 byway of fuel manifold 118 formed by the aligned apertures 124, 134, and124' of the plates. The fuel is introduced to the reactant-flowpassageways and is distributed over the bottom of the interconnectorplate 130B, and over the fuel electrode coating 120B of the electrolyteplate 120. Concomitantly, the sealer material 160A, prevents the inputoxidizer reactant from entering the reactant-flow passageways and thusmixing with the pure fuel/spent fuel reactant mixture. The absence ofany sealer material at the spent fuel manifold 119 allows spent fuel toenter the manifold 119. The fuel is subsequently discharged along theannular edge 131A of the interconnector plate 130. The flow path of thefuel reactant is illustrated by the solid black arrows 126C.

The dimples 140 of the interconnector surface have an apex 140A thatcontact the electrolyte plates, in assembly, to establish an electricalconnection therebetween.

A wide variety of conductive materials can be used for the thininterconnector plates of this invention. Such materials should meet thefollowing requirements: (1) high strength, as well as electrical andthermal conductivity; (2) good oxidation resistance up to the workingtemperature; (3) chemical compatibility and stability with the inputreactants; and (4) manufacturing economy when formed into the texturedplate configuration exemplified by reactant-flow passageways.

Materials suitable for the fabrication of interconnector plates includenickel alloys, nickel-chromium alloys, nickel-chromium-iron alloys,iron-chromium-aluminum alloys, platinum alloys, cermets of such alloysand refractory material such as zirconia or alumina, silicon carbide andmolybdenum disilicide.

The textured patterns of the top and bottom of the interconnector platecan be obtained, for example, by stamping the metallic alloy sheets withone or more sets of matched male and female dies. The dies arepreferably prefabricated according to the desired configuration of theinterconnector plate, and can be hardened by heat treatment to withstandthe repetitive compressing actions and mass productions, as well as thehigh operating temperatures. The stamp forming process for theinterconnectors is preferably conducted in multiple steps due to thegeometrical complexity of the gas passage networks, e.g., the dimpledinterconnector plate surface. The manifolds formed in the interconnectorplates are preferably punched out at the final step. Temperatureannealing is recommended between the consecutive steps to prevent theoverstressing of sheet material. The stamping method is capable ofproducing articles of varied and complex geometry while maintaininguniform material thickness.

Alternatively, corrugated interconnectors can be formed byelectro-deposition on an initially flat metal plate using a set ofsuitable masks. Silicon carbide interconnector plates can be formed byvapor deposition onto pre-shaped substrates, by sintering of bondedpowders, or by self-bonding processes.

The oxidizer and fuel reactants are preferably preheated to a suitabletemperature prior to entering the electrochemical converter. Thispreheating can be performed by any suitable heating structure, such as aregenerative heat exchanger or a radiative heat exchanger, for heatingthe reactants to a temperature sufficient to reduce the amount ofthermal stress applied to the converter.

Another significant feature is that the extended heating surfaces 131Dand 131C heat the reactants contained within the oxidizer and fuelmanifolds 117 and 118 to the operating temperature of the converter.Specifically, the extended surface 131D that protrudes into the oxidizermanifold 117 heats the oxidizer reactant, and the extended surface 131Cthat protrudes into the fuel manifold 118 heats the fuel reactant. Thehighly thermally conductive interconnector plate 130 facilitates heatingof the input reactants by conductively transferring heat from the fuelcell internal surface, e.g., the middle region of the conductiveinterconnector plate, to the extended surfaces or lip portions, thusheating the input reactants to the operating temperature prior totraveling through reactant flow passageways. The extended surfaces thusfunction as a heat fin. This reactant heating structure provides acompact converter that is capable of being integrated with anelectricity generating power system, and further provides a highlyefficient system that is relatively low in cost. Electrochemicalconverters incorporating fuel cell components constructed according tothese principles and employed in conjunction with a gas turbine or anHVAC system provides a power system having a relatively simple systemconfiguration.

The operating temperature of the electrochemical converter is preferablybetween about 20° C. and 1500° C., and the preferred fuel cell typesemployed by the present invention include solid oxide fuel cells, moltencarbonate fuel cells, alkaline fuel cells, phosphoric acid fuel cells,and proton membrane fuel cells.

FIGS. 3-5 illustrate interleaved plates that can be arranged to form afuel cell stack. However, the present invention is useful not only witha stack-type fuel cell, but with many other types of fuel cells known inthe art. For example a fuel cell element need not be a stack; that is,it need not be constructed as a stack of interleaved plates, but canhave, for example, a tubular configuration. Such a tubular fuel cellelement, or other shapes, known by those of ordinary skill in the art tobe useful, based on the disclosure herein, in the present invention, aredeemed within the scope of the invention.

According to the invention, the integration of an electrochemicalconverter with a bottoming device, such as the gas turbine illustratedin FIG. 1 or the HVAC system illustrated in FIG. 2, is aided by housingthe electrochemical converter 72 within a pressure vessel. A preferredtype of converter pressure vessel is illustrated in FIG. 6, where apressure vessel 220, which can also function as a regenerative thermalenclosure, encases a series of stacked fuel cell assemblies 222. Thepressure vessel 220 includes an exhaust outlet manifold 224 for routinggases collected by the pressure vessel 220 to a bottoming device,electrical connectors 226 and input reactant manifolds 228 and 230. In apreferred embodiment, the fuel reactant is introduced to the fuel cellstacks 222 through the centrally located manifolds 230, and the oxidizerreactant is introduced through the manifolds 228 located about theperiphery of the vessel 220.

The stacked fuel cell array 222 can vent exhaust gases to the interiorof the pressure vessel 220. The pressure of exhaust gases appropriate tothe bottoming device used in conjunction with the pressure vessel can becontrolled through use of a pump, such as the compressor 76 in FIG. 1,or the blower 98 in FIG. 2, selectively pumping an input reactant into,and hence exhaust gases out of, the electrochemical converter array 222.

As described above, the electrochemical converter can be operated at anelevated temperature and at ambient pressure or slightly above, as whenthe energy system employs an HVAC system as the bottoming device, or atan elevated pressure, as when the energy system employs a gas turbine,and wherein the pressure vessel and electrochemical converter acts asthe combustor of the gas turbine system. The electrochemical converteris preferably a fuel cell system that can also include an interdigitatedheat exchanger, similar to the type shown and described in U.S. Pat. No.4,853,100, which is herein incorporated by reference.

The pressure vessel 220 can include an outer wall 238 spaced from aninner wall 234, thereby creating an annulus 236 therebetween. Theannulus 236 can be filled with an insulative material for maintainingthe outer surface 239 of the pressure vessel 220 at an appropriatetemperature. Alternatively, the annulus can house or form a heatexchanging element for exchanging heat with the pressure vessel 220. Inone embodiment of a heat exchanger, the annulus 236 and walls 234 and238 can form a heat exchanging jacket for circulating a heat exchangingfluid therein. The heat exchanger formed by the walls 234 and 238 andthe annulus 236 exchanges heat with the pressure vessel and helpsmaintain the outer surface 239 of the pressure vessel at an appropriatetemperature. Of course the use of the annulus 236 as a cooling jacketdoes not preclude the additional use of an insulative material, locatedother than in the annulus 236, for reducing heat loss from the interiorof the pressure vessel 220 or for also helping to maintain the outersurface 239 of the pressure vessel at an appropriate temperature.

In one embodiment of the invention, the heat exchanging fluid circulatedin the pressure vessel heat exchanger, such as the cooling jacket formedby walls 234 and 238 and annulus 236, is an input reactant, such as theair input reactant flowing in the manifolds 238. In this embodiment, themanifolds 228 are essentially inlets that are in fluid communicationwith the portion of the annulus 236 adjacent the top 240 of the pressurevessel 220. Additional manifolding (not shown) fluidly connects theannulus 236 to the fuel cell stack 222 such that the air input reactantis properly introduced thereto. The preheating of the air input reactantby the cooling jacket formed by walls 234 and 238 and annulus 236 servesseveral purposes, including preheating the air input reactant to boostefficiency by regeneratively capturing waste heat, and cooling the outersurface 239 of the pressure vessel 220.

FIG. 7 illustrates a transition, or feedthrough, for use with thepressure vessel of the electrochemical converter power system, forducting exhaust gases from the interior of the pressure vessel through aconduit for transfer to a bottoming device.

The feedthrough 250, shown in FIG. 7, is designed to operate at bothhigh temperature and pressures, and includes an upper section 252, forattachment to the pressure vessel 220, and a lower section 254. An axialbore 256 passes through both the upper section 252 and the lower section254 for ducting, or transferring, a fluid, such as exhaust gas, from theinterior of the pressure vessel 220 to an appropriate conduit fortransfer of the exhaust gas to a bottoming device.

The feedthrough upper section 252 includes an outer pressure tube, orjacket, 260 having a flange 261 attached thereto for mating with aflange (not shown) of the pressure vessel 220. An annulus of thermalinsulation material 262 is disposed inside the tube 260. The pressuretube 260 terminates at a pressure disc, or cap, 264. The pressure disccan be welded at the joint 263 to the outer pressure tube 260. Thepressure disc can be welded at the joint 265 to the outer wall of aninner pressure tube 271.

The lower section 254 of the feedthrough 250 includes the inner pressuretube 271 having a lower flange 270 for attachment to a conduit (notshown). The inner tube 271 is attached, as noted above, at the joint 265to the pressure cap 264. The pressure cap 264 thus forms a pressuretight joint between the tubes 260 and 271. An annulus of insulation 272is disposed about the tube 271.

The upper section 252 of the feedthrough 250 thus transitions from anannulus of insulation 262 that is interior to the outer tube 260 to anannulus of insulation 272 that jackets the exterior of the innerpressure tube 271. The tube 271 has a small diameter for ease ofconnection with conduit.

FIG. 8 illustrates an energy system 310, in which an electrochemicalconverter 312 is enclosed in a pressure vessel 314 having a heatexchanging element 316, such as a cooling jacket 316. The bottomingdevice incorporated in the illustrated energy system 310 is a gasturbine 320, which extracts mechanical energy from waste heat in exhaustgases 315 generated by the electrochemical converter 312. Otherbottoming devices are possible, as discussed above.

The pressure vessel 314 can be regeneratively cooled by an oxidizerreactant 328, such as oxygen, or by other input reactants, such as water324, flowing in the heat exchanging element 316, such as the illustratedcooling jacket, or in a cooling coil. One of ordinary skill in the art,in accordance with the teachings herein, will readily appreciate thatthe heat exchanging element 316 can have various configurations. Forexample, the pressure vessel 314 can also be transpirationally cooled bya heat transfer fluid, such as oxidizer reactant 328, using an inwardflow through a porous structure (not shown) disposed about the pressurevessel 314. For an example of a transpirational cooling technique seeU.S. Pat. No. 5,338,622 of Hsu et. al., issued Aug. 16, 1994 andentitled "Thermal Control Apparatus," the teachings of which are hereinincorporated by reference. Alternatively, the heat exchanger element 316can include a cooling coil, having an inner lumen through which the heatexchanging fluid flows, and which is disposed about the pressure vessel314. In addition, a high temperature thermal blanket or cast caninsulate the vessel either internally, externally, or both. Typically,the pressure vessel 314 is cooled and/or insulated such that theexternal temperature is less than about 250° F.

The energy system 310 of FIG. 8 can operate without the heat exchangingelement 316, typically resulting in a higher temperature of the walls ofthe pressure vessel.

Electricity is generated by the energy system 310 in at least two ways.The electrochemical converter 312 is electrically connected to inverter318 for converting the direct current electrical energy generated by theconverter 312 into alternating current, and the turbine expander 326 ofgas turbine assembly 320 drives a generator 322. The turbine expander326 need not be used to generate electricity; its output could becoupled to devices other than the generator 322 to perform, for example,mechanical work, such as driving a shaft for an industrial process.

Input reactants to the electrochemical converter power system 310 caninclude, but are not limited to, a reforming agent 324, which cancomprise water; a fuel reactant input 326, such as natural gas, and anoxidizer input reactant 328, such as air. Input reactants 324 and 326can be pre-processed, according to techniques known to those of ordinaryskill in the art, by pre-processing apparatus 330. Pre-processingapparatus can include, for example, a desulfurization unit for removingsulfur compounds, which can harm the electrochemical converter 312, fromthe input fuel 326, and a filter for filtering the reforming agent 324.

In the illustrated embodiment, a compressor 332 draws the oxidizer inputreactant 328 through cooling jacket 316 and delivers the reactant 328under pressure to the electrochemical converter assembly 312, thuspressurizing the assembly 312 and causing exhaust gases 315 topressurize the interior 313 of pressure vessel 314. The electrochemicalconverter assembly 312 in conjunction with pressure vessel 314 thus actas a combustor, for the turbine expander 326 of the gas turbine assembly320. The compressor 332 can driven by a shaft 334 connected to theturbine expander 326, or alternatively, can be driven by a separatepower source (not shown).

In alternative embodiments not shown in FIG. 8, the oxidizer reactant328 can be circulated through the cooling jacket 316 by a blower or pumpprior to entering the electrochemical converter assembly 312. In thisinstance the exhaust 315 of the converter assembly 312 is usually routedto a heat actuated chiller, or a boiler, for use with an HVAC system.

A preheater 336, as is known in the art, can be employed to preheatinput reactants to the electrochemical assembly 312 before theirintroduction to the assembly 312. In the illustrated embodiment, thepreheater 336 preheats the oxidizer input reactant 328 after it leavesthe compressor 332. The pre-heater 336 extracts energy from the exhaustgases 315 prior to or following the introduction of the exhaust gases315 to the turbine expander 326 of the gas turbine assembly 320 in aregenerative fashion.

The electrochemical converter assembly 312 can include a reactantprocessor 346, such as a reformer, and temperature regulation apparatus348, in addition to a fuel cell array 350. The temperature regulationapparatus 348 can include that disclosed in U.S. Pat. Nos. 5,338,622 and5,462,817, both herein incorporated by reference. The fuel cell array350 and the reformer 346 can also be constructed as stacks. The stacksof the fuel cell 350, reformer 346 and temperature regulation apparatusstacks 348 can perform several functions, including the following:heating the electrochemical converter 312 on start-up, preheating one ormore of the input reactants 324, 326, and 328; preheating of thereactant processor 326; reforming an input reactant, such as the fuel326, and heating and cooling for temperature regulation under steadystate operation of the electrochemical converter assembly 312.

Temperature regulation of the electrochemical converter assembly 312 canbe accomplished by using the temperature regulation apparatus 348 in aheating mode by allowing the fuel and oxidizer to combust internaland/or external to the temperature regulation apparatus 348. Temperatureregulation can be accomplished under a cooling mode by allowing entry ofonly the oxidizer or other non-reacting gases, such as nitrogen, to thetemperature regulation apparatus 348.

The temperature regulation apparatus 348 can be used as a heater toprovide supplemental heat for maintaining a required operationaltemperature of the fuel cell arrays 350, or to heat the electrochemicalconverter apparatus 312 on startup. In some instances a anelectrochemical converter assembly 312, e.g., of a power rating lessthan 10 kW, can require heating to maintain the proper operatingtemperature of 1000° C. Further regulation methods include thermallyintegrated recuperation of outgoing hot exhaust and insulating theelectrochemical converter 312 or a portion thereof.

The reactant processor 346 can reform fuel, typically by receiving fueland steam as input reactants 326 and 324, respectively, and yielding H2and CO, which both then enter the fuel cell array 350, with which thereactant processor 346 is in fluid communication. Other reactions arepossible. For example, the reactant processor 346 can receive fuel andoxidizer and yield H₂ and CO, or receive fuel and steam and CO₂ andyield H₂ and CO. Reactant processor 346 can be enclosed to channel theflow of reactants 324 and 326 or to control the mixture of reactants andresultants. The reforming agent is typically regulated in proportion tothe fuel flow, considering agents such as steam flow, O₂, or the fuelexhaust, consisting of H₂ O and CO₂. The reactant processor 346 can bedisposed outside the pressure vessel 314, as is known in the art, or notused at all.

The fuel cell array 350 can receive the oxidizer 328 and reformed fuelfrom the reactant processor 346 to permit performance of theelectrochemical reaction. The fuel cell array 350, while producingelectricity, releases heat which can be received by the temperatureregulation apparatus 348. The fuel cell array 350 is typically designedto release fuel exhausts 315 to the interior 313 of the vessel 314, andthe exhaust 315 can be collected for recycling in reforming use or forother commercial feedstocks.

The fuel cell array 350 can also be operated in a reverse electrolysismode to consume electricity and to producing fuel species and oxidationspecies. Reverse electrolysis can require heating of the fuel cellarray, such as by the temperature regulation apparatus 348.

The fuel cell array 350 typically comprises multiple columns of fuelcell stacks, each stack having electrolyte plates or electrochemicalprocessing plates interleaved with and thermally conducting plates. Thereactant processor 346, can also have stacks which can be interdigitallypositioned among the stacks of the fuel cell array 350. The stacks ofthe reactants processor typically comprise chemical processing platesinterleaved with thermally conducting plates. The reactants processorstacks and the fuel cell stacks can be positioned interdigitally inrectangular, hexagon, or octagon pattern to achieve even thermaldistribution.

With the above arrangement, the reactant processor stacks 346 and thefuel cell stacks 350 are capable of reaching their individual isothermalstates in the plane of the conducting plates. The reactant processorstacks 346 and the fuel cell stacks 350 are also capable of reachingtheir individual isothermal states in the axial direction of the stacksassisted by the uniform distribution of the reactants flows. Combiningthe above two techniques, the fuel cell stacks 350 are capable ofreaching an isothermal state in the radial direction as well as in theaxial direction of the stacks.

The reactants processor stacks, the fuel cell stacks and the temperatureregulation stacks close to the walls of vessel 314 can be connectedindependently from the inner stack arrays, but be maintained at the sameoperation temperature as the inner arrays.

The pressure vessel 314 encloses at least the fuel cell array 350 andshould withstand the maximum pressure for the operation of theelectrochemical converter assembly 312. Although pressures can vary,typical design pressures range from 50-500 psi. A cylindrical vessel,designed to collect the hot exhaust products 315 of the electrochemicalconverter assembly 312 has designated ports, such as port 294. As noted,use of the pressure vessel 314 facilitates the collection of exhaustgases for efficient extraction of energy therefrom.

In one example, the vessel 314 encloses an electrochemical converterassembly 312 that includes a 25 kW Solid Oxide Fuel Cell (SOFC) as thefuel array 350 and has an internal diameter of approximately 24" and aheight of 24", and an external diameter of 34" and a height of 36".Feedthroughs 290 and 292 for reactants, feedthrough 294 for exhaust, andfeedthrough 296 for electricity are placed on the bottom plate, orotherwise disposed on the periphery of the enclosure vessel 314.

It will thus be seen that the invention efficiently attains the objectsset forth above, among those made apparent from the precedingdescription. Since certain changes may be made in the aboveconstructions without departing from the scope of the invention, it isintended that all matter contained in the above description or shown inthe accompanying drawings be interpreted as illustrative and not in alimiting sense.

It is also to be understood that the following claims are to cover allgeneric and specific features of the invention described herein, and allstatements of the scope of the invention which, as a matter of language,might be said to fall therebetween.

Having described the invention, what is claimed as new and desired to besecured by Letters Patent is:
 1. An electrochemical converter powersystem, comprisingan array of electrochemical converters for generatingpower, said array adapted for receiving input reactants, a pressurevessel disposed about said array of electrochemical converters, saidpressure vessel collecting exhaust gases generated by saidelectrochemical converters when said converters are operating, and meansfor exhausting said collected exhaust gases from said pressure vesselfor use external thereto.
 2. The electrochemical converter power systemof claim 1, further comprising a reactant processor disposed inside saidpressure vessel and in fluid communication with said array ofelectrochemical converters.
 3. The electrochemical converter powersystem of claim 2, wherein said reactant processor comprises a pluralityof reactant processor elements, each said reactant processor elementincluding chemical processing plates interleaved with thermallyconducting plates.
 4. The electrochemical converter power system ofclaim 2, wherein said electrochemical converter array comprises aplurality of fuel cell elements in the form of stacks includingelectrolyte plates interleaved with thermally conducting plates,andwherein said reactant processor includes multiple reactant processorelements, said reactant processor elements in the form of stacks havingchemical processing plates interleaved with thermally conducting plates.5. The electrochemical converter power system of claim 4, wherein saidreactant processor stacks are columnar and are interdigitally positionedamong said fuel cell stacks.
 6. The electrochemical converter powersystem of claim 4, wherein at least one of said reactant processorelements includes means for attaining a radial isothermal condition, andwherein at least one of said fuel cell elements include means forattaining a radial isothermal condition.
 7. The electrochemicalconverter power system of claim 4, wherein at least one of said reactantprocessor elements includes reactant flow means for reaching anisothermal condition in an axial direction, and wherein at least one ofsaid fuel cell elements include reactant flow means for reaching anisothermal condition in an axial direction.
 8. The electrochemicalconverter power system of claim 4, wherein at least one of said fuelcell elements include means for attaining a radial isothermal conditionand means for attaining an axial isothermal condition.
 9. Theelectrochemical converter power system of claim 2, wherein said reactantprocessor elements are interdigitally positioned among said fuel cellelements.
 10. The electrochemical converter power system of claim 2,wherein said reactant processor elements and said fuel cell elements areinterdigitally arranged in a selected pattern to equalize thedistribution of thermal energy among said elements in said pattern, saidpattern being selected from the group consisting of a rectangularpattern, a hexagonal pattern, and an octagonal pattern.
 11. Theelectrochemical converter power system of claim 2, wherein said pressurevessel includes a wall bounding the interior of said pressure vessel,and wherein said reactant processor element includes processor elementslocated proximate to the wall of said pressure vessel and elementslocated distal from the wall of said pressure vessel, and wherein saidelectrochemical converters include fuel cell elements disposed proximateto the wall and fuel cell elements located distal to the wall,said fuelcell elements and said reactant processor elements located distal to thewall being operated independently of said reactant processor elementsand said fuel cell elements located proximate to said wall, and whereinsaid electrochemical converter power system includes means for operatingsaid fuel cell elements proximate to said vessel wall and said reactantprocessor elements proximate to said vessel wall at about the sametemperature as said fuel cell elements distal from said vessel wall andas said reactant processor elements distal from said vessel wall. 12.The electrochemical converter power system of claim 2, wherein saidreactant processor comprises fuel reforming means for receiving fuel andsteam input reactants and forming hydrogen and carbon monoxideresultants from said reactants.
 13. The electrochemical converter powersystem of claim 2, wherein said reactant processor includes fuelreforming means for receiving fuel and oxidizer input reactants andforming hydrogen and carbon monoxide resultants from said reactants. 14.The electrochemical converter power system of claim 2, wherein saidreactant processor comprises fuel reforming means for receiving fuel,steam and carbon dioxide input reactants and forming hydrogen and carbonmonoxide resultants from said reactants.
 15. The electrochemicalconverter power system of claim 2, wherein said reactant processorincludes fuel reforming means for receiving input reactants to form aresultant therefrom, said reactant processor including at least onereactant processor stack comprising chemical processor platesinterleaved with thermally conducting plates, said reactant processorstack having an enclosure for controlling the flows of input reactantsto said reactant processor stack and of resultants generated by saidreactant processor stack.
 16. The electrochemical converter power systemof claim 1, further comprising a reactant processor disposed external tosaid pressure vessel and in fluid communication with said array ofelectrochemical converters.
 17. The electrochemical converter powersystem of claim 1, wherein said electrochemical converter arraycomprises multiple fuel cell elements, each said fuel cell elementincluding electrolyte plates interleaved with thermally conductingplates.
 18. The electrochemical converter power system of claim 11wherein said fuel cell elements are adapted for receiving fuel andoxidizer reactants for reforming of said fuel reactant and for powergeneration within said fuel cell elements.
 19. The electrochemicalconverter power system of claim 17 wherein said fuel cell elementsgenerate and release fuel cell exhaust gases to the interior of saidpressure vessel.
 20. The electrochemical converter power system of claim19, further comprising means for collecting said fuel cell exhaust gasesfor further processing, said further processing selected from the groupconsisting of recycling said exhaust gases for reforming use andcogeneration of energy employing said exhaust gases.
 21. Theelectrochemical converter power system of claim 17 furthercomprisingmeans for operating said fuel cell elements in a reverseelectrolysis mode wherein said fuel cell elements consume electricityand produce fuel species and oxidation species, heater elements forsupplying heat to said fuel cell elements, and said fuel cell elementsincluding receiving means for receiving heat from said heater elements.22. The electrochemical converter power system of claim 1, wherein saidelectrochemical converter array comprises a plurality of fuel cellelements, each said fuel cell element having a tubular configuration.23. The electrochemical converter power system of claim 22 wherein saidfuel cell elements are adapted for receiving fuel and oxidizer reactantsfor reforming of said fuel reactant and for power generation within saidfuel cell elements.
 24. The electrochemical converter power system ofclaim 22 further comprising cooling elements adapted for receiving heatgenerated by said fuel cell elements.
 25. The electrochemical converterpower system of claim 22 wherein said fuel cell elements generate andrelease fuel cell exhaust gases to the interior of said pressure vessel.26. The electrochemical converter power system of claim 22 furthercomprisingmeans for operating said fuel cell elements in a reverseelectrolysis mode wherein said fuel cell elements consume electricityand produce fuel species and oxidation species, heater elements forsupplying heat to said fuel cell elements, and said fuel cell elementsincluding receiving means for receiving heat from said heater elements.27. The electrochemical converter power system of claim 1, wherein saidpressure vessel is configured to withstand pressures up to about 1,000psi.
 28. The electrochemical converter power system of claim 1, whereinsaid pressure vessel comprises a cylindrical pressure vessel.
 29. Theelectrochemical converter power system of claim 1, further comprising aheat exchanging element coupled to said pressure vessel to exchange heattherewith, said heat exchanging element adapted for exchanging heat withsaid pressure vessel by flowing a heat exchanging fluid through saidheat exchanging element.
 30. The electrochemical converter power systemof claim 29 wherein said heat exchange fluid includes at least a firstof said input reactants, said first input reactant flowing through saidheat exchanger prior to the introduction of said first reactant to saidelectrochemical converter.
 31. The electrochemical converter powersystem of claim 29, wherein said heat exchanging fluid includes anoxidizer input reactant, and said system further comprises means formaintaining the temperature of an external wall of said pressure vesselbelow about 250° F.
 32. The electrochemical converter power system ofclaim 29, wherein said heat exchanging element includes a heatexchanging jacket disposed about said pressure vessel and having aporous wall, and said positive pressure vessel is transpirationallycooled by said heat exchanging fluid comprising an oxidizing inputreactant flowing through said porous wall.
 33. The electrochemicalconverter power system of claim 29, wherein said heat exchanging fluidcomprises an oxidizer input reactant, and said system further comprisesa compressor for drawing said input reactant through said heatexchanging element.
 34. The electrochemical converter power system ofclaim 1, further comprising high temperature thermal insulation disposedadjacent the wall of said pressure vessel.
 35. The electrochemicalconverter power system of claim 1, further comprising means forregulating the flow of a fuel input reactant to said electrochemicalconverter array to produce a selected power output of saidelectrochemical converter.
 36. The electrochemical converter powersystem of claim 1, further including means for regulating the flow of afuel input reactant to said electrochemical converter to maintain aselected operating temperature of said electrochemical converter. 37.The electrochemical converter power system of claim 1, wherein saidinput reactants include a reforming agent and a fuel, said power systemfurther comprising means for regulating the flow of said reforming agentto be proportional to the flow of said fuel input reactant.
 38. Theelectrochemical converter power system of claim 1, further comprisingmeans for collecting exhaust produced by said electrochemical converterarray at or near the operating temperature of said array and at or nearthe pressure of exhaust gases from said array.
 39. The electrochemicalpower system of claim 1, further comprising a recuperator, and means forintroducing exhaust gases produced by said electrochemical converterarray to said recuperator for preheating said input reactants.
 40. Theelectrochemical power system of claim 1, further including a heatexchanger, and means for introducing exhaust gases produce by saidelectrochemical converter array to said heat exchanger for thecogeneration of energy.
 41. The electrochemical converter power systemof claim 1, further comprising a gas turbine, and means for introducingexhaust gases generated by said electrochemical converter array to saidgas turbine to generate power.
 42. The electrochemical converter powersystem of claim 41, including a recuperator for preheating said inputreactants with said exhaust gases generated by said electrochemicalconverter array.
 43. An electrochemical converter system for use with abottoming device, comprisingan electrochemical converter array adaptedfor receiving input reactants; a positive pressure vessel disposed aboutsaid electrochemical converter assembly; a heat exchanging elementdisposed relative to said pressure vessel for exchanging heat therewith,said heat exchanging element being in fluid communication with saidelectrochemical converter array for delivering said input reactantsthereto; and a blower in fluid communication with said heat exchangingelement for circulating a heat transfer fluid comprising an inputreactant through said heat exchanging element for transferring heatbetween said pressure vessel and said input reactant prior to deliverythereof to said electrochemical converter array.
 44. The electrochemicalconverter system of claim 43, wherein said blower is adapted to drawsaid heat exchanging fluid through said heat exchanging element.
 45. Theelectrochemical converter system of claim 43, wherein said blower isadapted to blow said heat exchanging fluid through said heat exchangingelement.
 46. The electrochemical converter system of claim 43, whereinsaid electrochemical converter array includes a plurality of electrolyteplates alternately stacked with interconnection plates.
 47. Theelectrochemical converter system of claim 43, wherein saidelectrochemical converter includes a fuel reformer for reforming aninput reactant.
 48. An electrochemical converter power system,comprisingan electrochemical converter adapted for receiving inputreactants, a pressure vessel disposed about and in thermal communicationwith said converter, said electrochemical converter venting exhaustgases comprising spent input reactants to the interior of said pressurevessel, a heat exchanging element coupled to said pressure vessel forexchanging heat therewith, said heat exchanging element adapted forexchanging heat at least with said pressure vessel by flowing a heatexchange fluid including a selected input reactant through said heatexchanging element prior to introduction of said selected reactant tosaid electrochemical converter, and cogeneration bottoming meansarranged to receive heated exhaust gases generated by saidelectrochemical converter.
 49. The electrochemical converter powersystem of claim 48, wherein said electrochemical converter is a fuelcell selected from the group consisting of a solid oxide fuel cell, amolten carbonate fuel cell, a phosphoric acid fuel cell, an alkalinefuel cell, and a proton exchange membrane fuel cell.
 50. Theelectrochemical converter power system of claim 48, wherein said systemfurther includes exhaust means for collecting exhaust gases collected bysaid pressure vessel at a temperature near the operating temperature ofsaid electrochemical converter and at a pressure near the pressure ofspent reactants within said electrochemical converter, said exhaustmeans being in fluid communication with said cogeneration means fordelivery thereto of said exhaust gases.
 51. The electrochemicalconverter power system of claim 48, further comprising a recuperator forrecuperating heat from said exhaust gases for preheating a first of saidinput reactants prior to introduction of said first input reactant tosaid electrochemical converter, said recuperator receiving said exhaustgases from said exhaust means and delivering said exhaust gases to saidcogeneration bottoming means.
 52. The electrochemical converter powersystem of claim 48, further including a drawing pump for drawing saidheat exchanging fluid through said heat exchanging element and fordelivery of said heat exchanging fluid to said electrochemicalconverter.
 53. The electrochemical converter power system of claim 48,wherein said cogeneration bottoming means comprises a gas turbine, andthe compressor section of said turbine draws said heat exchanging fluidthrough said heat exchanging element and delivers said heat exchangingfluid to said electrochemical converter.
 54. The electrochemicalconverter power system of claim 53, further comprising an electricgenerator coupled to said gas turbine.
 55. The electrochemical converterpower system of claim 53, further comprising a recuperator forpreheating with exhaust gases generated by said gas turbine a firstinput reactant before introduction of said first input reactant to saidelectrochemical converter.